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CryptoHack

A free, fun platform for learning modern cryptography

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Learn By Doing

Learn about modern cryptography by solving a series of interactive puzzles and challenges. Get to know the ciphers and protocols that secure the digital world by breaking them.

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Level Up

Earn points by solving challenges. Finish categories to earn trophies and gain levels to track your progress. Can you reach the top of the scoreboard?

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Fresh Challenges

We are constantly creating new challenges to keep your crypto knowledge up to date. Expect exciting brainteasers and whole new categories as the site continues to grow.

New Challenges
ECLCG (HITCON CTF) CTF Archive 0
Sus (ImaginaryCTF) CTF Archive 0
Share (HITCON CTF) CTF Archive 0
Leet Universe (ImaginaryCTF (Daily)) CTF Archive 0
Hyper512 (HITCON CTF) CTF Archive 0
Weekly Top Users
#1 Triode 4290
#2 infernosalex 3510
#3 milaiscute 2530
#4 ECM 2465
#5 striving 1960
Recent Solves
Adrien's Signs groundhog
Extended GCD pipoVigne
ASCII harshwardhan
Base64 Polaris_wzh
Extended GCD hashirali
Recent Solutions
Hamiltonicity 2 klmn 0
Breaking SIDH klmn 0
Where's the Supersingular Curve marc_t0k 0
The j-invariant marc_t0k 0
JSON in JSON Legacyy 0

Level Up

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